The manufacturing of an automotive seat assembly may incorporate any number of different processes. For example, foam cushions for seat bottoms and seat backs may be glued or steam heated to a respective trim cover material. The trim covers may be pre-sewn and may or may not include trim strips, as are well known in the art. Foam cushions for side bolsters may also be glued or steam heated to a trim cover material. Further, pre-sewn side bolsters and/or pre-sewn headrests may be injected with a liquid foam. Foam injection processes are well known in the art and include a number of different manufacturing techniques.
A typical foam injection technique first includes pre-sewing the intended seating component, i.e., a headrest. The pre-sewn trim cover material must be protected against the injected liquid foam. Typically, a thin foam sheet with a plastic liner is adhered to the inside surface of the trim cover. The foam sheet provides for extra cushion and the plastic liner protects the foam sheet from the injected liquid foam. The plastic liner prevents any absorption of the liquid foam by the foam sheet. The pre-sewn trim cover typically forms a type of envelope with an opening therein. The envelope is then placed within a cast wherein the interior of the cast incorporates the desired shape of the seating component. The liquid foam is injected within the trim cover envelope and allowed to cure and harden to form the final padded product. A major difficulty in this foam injection process is ensuring that no liquid foam leaks through the seams in the pre-sewn trim cover envelope. If leakage does occur, the product is aesthetically displeasing and unmarketable.
The current method of sealing the seams is to sew additional strips of foam over the seams. The additional foam strips are known in the art as scam seal tape. Seam seal tape attempts to stop leakage by absorbing a portion of the injected liquid foam. The absorption occurs because the foam strips do not have any plastic liner adhered thereto. This method of sealing seams in a pre-sewn trim cover envelope, however, has a number of deficiencies. First, the foam strips are relatively expensive and difficult to use. The flexibility of the foam strips can cause a number of problems during the sewing process. For example, the foam strips can be difficult to guide and align with the seams. Further, if the foam strips are stretched excessively or torn then leakage through the seams may occur. Additionally, the foam strips harden from the absorption of the liquid foam, which creates a hard undesirable seam.